WSP10689

• File Number: 8273.600
• Description: Colorado River Basin Salinity Control - Federal Agencies - USDA
• Basin: Colorado Mainstem
• Water Division: 5
• Date: 1/1/1994
• Author: USDA
• Title: Grand Valley Salinity Project - 1993 Annual Monitoring and Evaluation Report
• Water Supply Pro - Doc Type: Annual Report

Co~parison of surge and conventional irrigation showed that the
reduction in water application per acre was directly related to the
number of hours of water applied per acre. With surge, the
'reduction in hours per acre of water applied compared to
conventional irrigation varied from 19 to 53 .hours.This related
to an average savings of 20\ or 9 hours per acre of water .
"w) i ""T.inn .with the use of. surge systems (Table. 5l.' .This'meant a
reduction of'about 23.3' in water application to the field. Water
'app1ication savings ranged from 5.4 to 13.3 acre inches per acre
for the.two, comparison fields; the average savings was about 9.3
acre inches per acre (Table 5). . .

'~ Comparison between surge and conventional irrigation also showed a
reduction in tailwater amount with surge. On the average there was
a 2.2 acre inches per acre reduction (Table S) for the season,
abo'!.\:: 21. 6' savings. . . . .

w
~
~
.~

With reduced water application at s"Ilrgesites," infiltrated depth
also decreased by an average of 7.1 inches per acre, about 23.8' .
savings (TableS). The reduction in infiltrated depth also helped
reduce deep percolation. Table.S shows that deep percolation
reduction is directly proportional to infiltrated depth.

Reduction in infiltrated depth and deep percolation helped increase
application efficiency at surge sites by an average of 7.4' in
1993; 9.4' in 1992, 4.7% in 1991 and about 12% in 1990. The
difference in application efficiency between surge and conventional
.sitEls v~ried from-0.8%to 15.5% for the 1993 season (Table 5). .

The difference in deep percolation reduction with use of surge
irrigation system varied from 1.1 acre inches.to 8.0 acre inches
per acre. Data from comparison sites indicate that deep
percolation could be reduced by about 4.6 acre inches per acre'with
the use. of surge systems,' a' savings of about. 90.2\ I for the season .
(Table 5). . However,it must .be emphasized that the fields .
monitored in 1993 for comparison purposes are owned by two of the
more progressive farmers in the Valley and savings of 90.2% in deep
percolation would not be the norm for the area. But data collected
from comparison sites between 1990 and 1993, does show deep
percolation savings to range from 15.8% to 90.2% or from 2~4 to
10.3 acre inches per acre or about 5.4 inches average savings
(Table 5).

e. Trends

.
Irrigation Trends: A comparison of nine years of irrigation data
(Table 4) shows that water application, deep percolation and
irrigation efficiency did not vary much over the years to be
significantly different with the exception of 1985. In 1985, a
full year of monitoring data was collected for the first time.

22

c..;':"

.:;.....:.'
';.::,'

?"/; .1
"-'.~
I

I
I
I
1